cciss: factor out fix target status processing code from sendcmd functions

Factor out code to process target status of completed commands in sendcmd()
and sendcmd_withirq_core(), and fix problem that bad target status was ignored in
sendcmd_withirq_core.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>